Everything you need to know about compliant diesel cars in 2023

It’s worth looking into what makes a diesel engine vehicle compliant. Read on to get everything you need to know in order to understand whether your car is compliant, whether you can make it compliant, and what to expect in a compliant diesel vehicle.

What is a compliant diesel car?

Compliance with ULEZ, and nearly every other CAZ in the UK, including Scotland’s Low Emission Zones, is based on your diesel or diesel hybrid car having an engine rating of at least Euro 6.

The Euro rating of your engine looks at how much NOx and particulate matter is emitted when you drive. People do not have to get their own vehicles individually rated; each car model released has an official Euro rating.

Most new diesel and diesel hybrid models since 2016 have had Euro 6 ratings, so if your diesel vehicle is fairly new, the likelihood is that you’re compliant. However, it’s still crucial to check your compliance in order to avoid unexpected charges and fines.

How to check a car’s Euro rating?

The quickest, easiest, and free way to check that your diesel vehicle is compliant with Euro 6 is by simply entering your reg in Motorway’s ULEZ checker.

Motorway’s ULEZ Checker (Image: Motorway)

Motorway’s ULEZ Checker indicates whether your vehicle is compliant with Euro 6, which is the criteria for being compliant with ULEZ and most of the UK’s other Clean Air Zones.

Alternatively, you can find your V5C logbook, which should state what your model’s engine Euro rating is.

You can also look up your car model spec online, to try to find the same info. If your model contains a word like SCR or Blue/AdBlue, it means you’re more likely to be compliant, as these indicate that there is a system in place to reduce the emissions in your exhaust.

Is it possible to make a diesel car compliant?

If you have a non-compliant car or van and would rather keep it than sell it, you can look into options to retrofit it in line with the Clean Vehicle Retrofit Accreditation Scheme (CVRAS).

Unless you qualify for a grant to retrofit your vehicle, which is more likely if you have a van and operate a small business or charity, or have a disabled tax class, retrofitting will likely be a much more costly option than selling and replacing your non-compliant vehicle. Retrofitting typically starts at a couple of thousand pounds.

Upgrading a sub-Euro 6 diesel to meet compliance will mean replacing the engine, likely including an AdBlue system, paying for your own testing to determine that your car emits a compliant level of pollutants, and then obtaining a Certificate of Conformity to prove your vehicle’s emissions levels.

AdBlue reduces emissions in many compliant diesel vehicles by mixing with the car exhaust and converting pollutants into harmless by-products (Image: Motorway)

It’s a costly and time-consuming process, and since your reg will still likely show up as belonging to a non-compliant model, you’ll have to register your Certificate of Conformity with any and all CAZs and LEZs that you drive through, in order to avoid penalty charge notices.

You may also have to coordinate with the DVLA about your road tax band, as this is determined by your emissions, again found in your vehicle’s spec.

Although you can retrofit a diesel car to make it compliant, it’s often far simpler to just sell your vehicle and buy a compliant one to replace it.

Which cars are compliant with Euro 6?

The vast majority of newer petrol and diesel engine cars are compliant with Euro 6 emissions regulations. This even includes larger family cars and SUVs, although it’s still crucial to check each vehicle spec for compliance.

Even though certain models are compliant with Euro 6, which will allow them to drive freely in most CAZs like ULEZ, they still might not benefit from the lowest possible road tax rates, depending on how high their emissions actually are.

If you want to be sure to be compliant with all regulated emissions zones, as well as benefitting from the lowest possible road tax rates, and any possible future levies on cars that emit pollutants, you can look to buy a battery-electric vehicle or a zero-emission vehicle, which does include some diesel hybrids.

Ready to save on running costs?

If you drive a diesel vehicle that doesn’t pass the Euro 6 compliance check, you’ll likely save a lot on running costs by selling it and investing in a compliant model, which are easy to find in the new and used-car markets.

When you sell your car on Motorway, dealers compete to give you their best price. You can have a sale agreed within 24 hours! (Image: Motorway)

It’s fast, easy, and free to sell your non-compliant vehicle on Motorway. Since their network of over 5,000 verified dealers are found all over the UK, there could still plenty of road left for your non-compliant car in regions with fewer emissions zones, and where fuel efficiency is more important than compliance.

Get started today with an instant, free valuation.